In clinical practice, various types of antibiotics and synthetic antimicrobial agents have been used for treating infectious diseases. However, recently, resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and penicillin-resistant Streptococcus pneumoniae (PRSP) have been reported, and therapeutic treatment of patients infected with such resistant bacteria is a critical issue. In addition, multidrug-resistant bacteria, which have developed resistance to a plurality of drugs, have appeared. Infectious diseases due to multidrug-resistant bacteria are intractable and are severe problems worldwide.
The development of antibiotics effective on these resistant bacteria has been strongly desired, and, for example, International Patent Publication No. WO 99/07682 (Patent Document 1) discloses quinolone compounds that are effective against MRSA. International Patent Publication No. WO 2004/002490 (Patent Document 2) and WO 2004/002992 (Patent Document 3) disclose compounds of which the working mechanisms are different from those of conventional medicaments.
Patent Document 1: International Patent Publication No. WO 99/07682
Patent Document 2: International Patent Publication No. WO 2004/002490
Patent Document 3: International Patent Publication No. WO 2004/002992